Liquid Crystal Displays (LCDs) are rapidly displacing cathode ray tubes (CRTs) across a variety of industries. The benefits of LCDs, and the drop in cost over time, have facilitated this transition. LCDs, for example, use anywhere from ⅓ to 60% less energy than a typical CRT. Further, LCDs do not emit the Very Low Frequency and Extra Low Frequency electromagnetic radiation emitted by CRTs. It is thought that these electromagnetic emissions may be harmful to one's health, making LCDs an attractive alternative for those who spend a great deal of time using a display of one type or another.
In addition to the above, CRTs generally include mercury, lead, and glass in relatively high amounts, all of which can lead to environmental concerns when a CRT is no longer in use and must be disposed of. LCDs do not typically have the same environmental problems related to disposal as do CRTs. Finally, LCDs have better contrast than CRTs, making them well-visible in lower levels of ambient lighting than a typical CRT. Thus, use of an LCD can provide energy savings in terms of ambient lighting as well as the energy usage of the device itself. Further, the better contrast leads to fewer fatigue problems among users, particularly when levels of ambient light are lower.
Despite the advantages of the LCD over the CRT, there are still problems associated with the use of LCDs in various industries, and even in the home. A primary problem associated with the use of LCDs is the thin glass that protects the LCD. The glass or plastic surface of an LCD could be as little as 1 millimeter thick. This thinness is not only desirable from a marketing standpoint, but is actually required due to the nature of the device. Because light emitted from an LCD travels through a variety of media, the viewing angle of an LCD is narrowed as compared to that of a CRT. This can result in the inability to properly see images, or to experience color-shifts when viewing the screen from other than substantially in front of the display. The thickness of the glass surface of the LCD can directly impact the viewing angle of the device, and therefore thin glass must be used to preserve the desired viewing angle.
The thin glass of an LCD is, of course, susceptible to being damaged by both sharp and blunt objects, industrial or other cleaners, and the like. In the restaurant industry, for example, LCD monitors are often used to indicate to a kitchen what items must be prepared in order to fulfill an order. The personnel working in the kitchen are generally using knives, forks, and other implements, and often use such items to point at the display in order to convey information to other workers. With the CRTs of the past, this behavior was not problematic due to the thickness of the glass used in the CRT. With LCDs, however, knives and other objects are routinely inadvertently used to pierce or otherwise damage the glass surface of the LCD. This leads to a substantial cost to a business of replacing LCD monitors. Likewise, small children in a home may inadvertently damage the LCD, or accidents either in the home or the workplace may damage such a display. Also, when an LCD becomes dirty, as happens frequently in, for example, restaurant and industrial uses, the screen is easily damaged during cleaning due to the harsh nature of some cleaners or the lack of skill of the person doing the cleaning.
Therefore, it would be beneficial to provide a lightweight, inexpensive, readily-cleanable protective covering for LCD displays.